Compression ignition engine



Jan. 12, 1937. R, R RAMSEY 2,067,461

COMPRESSION IGNITION ENGINE Filed Sept. 24, 1956 2 Sheets-Sheet 1 l/ I I1 4 10 K14 I 7 F. F 1 3mm 1 9 1 R. P. RAMSEY COMPRESSION IGNITIQN ENGINEJan. 12, 1937.

Filed Sept. 24, 1936 4 2 Sheets-Sheet 2 Patented Jean, 1931.

UNITED STATES PATENT OFFICE 2.061.461 compssron rcnrrron ENGINE RobertP. Ramsey, Philadelphia, Pa, assignor to. The National Supply Co. ofDelaware, Toledo, Ohio, a corporation of Delaware Application September24, 1936, Serial No. 102,379

2 Claims. (a 123-32) vision ofmeans to accomplish the most advantageouscombustion of the fuel injected into a compression ignition engine.

Another object of the invention is the provision of a means forcontrolling the combustion of fuel, portions of which assume difierentphysi-.

cal states upon injection, which consists in providing for each portionair in the conditions most desirable for the advantageous burning ofthat portion.

Another object of the invention is the provision of an apparatus,wherein main and auxiliary combustion chambers are provided and so.disposed with .relation to a fuel injection nozzle that portions of thefuel spray in different physical conditions are fed to the two chambers,and the air in the respective chambers is in the proper condition ofturbulence required to burn advantageously the part of the fuel in thatchamber.

More specifically an object of the invention is to inject a, fuel streamthrough a chamber containing relatively quiescent air, into which the 7highly atomized envelope of the stream distributes itself, while thedense core of the stream passes into a chamber containing rapidlyswirling air with which it is mixed. I

Other objects and advantages of the invention will become apparent asthe description proceeds, reference being had to the accompanyingdrawings, in which- Figure 1 is a fragmentary sectional view with partsin full, of an engine embodying the present invention, the section beingtaken on line l-l of Fig. 2; Fig. 2 is a section on line 2-2 of. Fig. 1;Fig. 3 is a somewhat diagrammatic sectional view of the combustionchambers showing a longitudinal section through a typical fuel nozzleand spray; Fig. e is an enlarged view of a nozzle tip; Fig. 5 is across-sectional view through a typical fuel spray, and Fig. 6 isatypical indicator diagram tak n dinin operation of an engine constructedin accordance with the present invention. Referring to the drawing thepresent invention is shown in connection withan engine having a cylindert surrounded ,byjja water jacket 2 substantially its entirejworklnglength. A piston 3 works in the bore of the cylinder in the usualmanner.

The present invention is particularly directed to the cylinder head partof the engine, which includes a body 4 bolted to the cylinder block andspaced therefrom by suitable gaskets '5. A

fuel injection nozzle 6 is seated in one side of the head and isdisposed to discharge fuel directly into a main combustion chamber I.The fuel injection nozzle is preferably of the pintle type and includesa reciprocating plunger 20 having a conical seat 2| adjacent its forwardend, which is adapted to cooperate with a congruous conical surface 22formed in the body of the nozzle. The nozzle opening 23'communicateswith the interior of the nozzle and is made slightly larger than thepintle 24, which projects through the opening. The pintle is formed-withreversely conical surfaces 25 and 25 at its tip which control to a.certain extent the angularity of the spray discharge. The plunger isbacked by a spring 21, which controls the pressure required to open thenozzle, so that fuel may discharge into the cylinder head. Fuel isintroduced into the nozzle through a passage 18 under a predee terminedpressure and this pressure, exerted on the forward end of the plunger20, lifts the conical valve 2| from its seat so that fuel may passthrough the opening 23 around the pintle 24.

The main combustion chamber 1 is open at its bottom to the cylinder andis shaped to present a minimum of surface for the dissipation of .heatand to form a space suited to permit the outer spray envelope of the f ljetfrom the nozzle 6 to distribute itself most oroughly and mingle withthe air in the chamber. To this end, the chamber is preferably made toflare from the injection nozzle so that the conical spray discharge willnot impinge on the side walls of the chamber. The dimension of this maincombustion chamber in the line axially of the fuel injection nozzle 6 isdictated by the consideration that the atomized portion, or sprayenvelope, of the injected jet of fuel penetrates the compressed gas inthe chamber only a certain distance for a given injection andcompression pressure, It is desirable that the spray envelope of the jetbe confined within the walls of the main combustion chamber for apurpose. which will presently become apparent.

It has been-found that the discharge from a nozzle of the pintle type isdivided into two parts 0 which differ widely in their physicalcharacter, istics. As shown in Figs. 3 and 4, the spray pattern shows acore C of fuel which is in substan- 'tially solid, coarsely atomized,form surrounded by an envelope 1) of highly atomized fuel partization,penetrates only arelatively small distancev into the heavy compressedatmosphere in'the cylinder head, and also, due to its fine atomization,

is adapted to burn quickly and smoothly in a quiescent volume of air. Onthe other hand, the substantially liquid central core C of the fuelspray will penetrate a much greater distance in the heavy atmosphereand, before it can be efllciently burned, must be broken up to beintermingled with air particles required for combustion.

While the invention has been disclosed in connection with a nozzle ofthe pintle type, it should be appreciated that any other nozzle whichdischarges a spray having similar characteristics of core and envelopemay be used.

In order to burn the coarse central core 0 of the fuel stream, anauxiliary combustion chamber 9 is provided at the opposite sideof themain combustion chamber 1 to the injection nozzle. The chamber 9 iscylindrical in form and its axis is preferably parallel to the axis ofthe working cylinder I. The auxiliary combustion chamber 9 communicateswith the main combustion chamber i through a passage l0 which is axiallyaligned with the fuel injection nozzle 6 and which may be belled, orslightly enlarged at its opening into the combustion chamber i to anextent such that it includes the heavy liquid part of the injected fuelspray. The opening of the passage I0 into the auxiliary combustionchamber 9 is disposed tangentially of the cylindrical wall of thelatter, so that a rapid swirl of air in the auxiliary combustion chamberis set up when air is forced into the main chamber and thence into theauxiliary chamber by an upward movement of the piston 3 on thecompression stroke of the engine. The swirling will continue during theinjection of the heavy central core of the fuel spray into the chamber,and causes the core to be broken up and thoroughly intermingled with theair in the auxiliary chamber.

A suitable air inlet valve I5 is seated in the roof of the maincombustion chamber I. Air introduced through this valve scavenges theburned gases from both combustion chambers l and 9 on the intake strokeof the piston and also serves to reduce the temperature of the valveseat and valve head, thus promoting longer life of these parts.

An exhaust valve I6 is seated in the cylinder 3 head immediatelyoverlying the piston space.

While the engine starts rapidly from cold, it may be desirable toprovide emergency means to temporarily increase the compression ratio ofthe engine when it becomes necessary to start under extreme conditions,as when the engine has been standing for some time in extremely coldweather. For this reason a plug valve Id is placed in the passage 40 tointerrupt communication between the main and auxiliary combustionchambers during the starting period. The valve may be operated by anysuitable means, manual or automatic. It will be appreciated that whenthis valve is closed the compression ratio of the engine is increased bythe extent that the available compression space is diminished. Obviouslythe increase in compression causes an increase in resulting airtemperature which, in turn, promotes rapidcold starting.

The operation of the present engine is such that the division of thefuel spray is made in accordance with its physical conditions. In theexample shown, the finely atomized portion remains in the main chamberand the relatively solid core is shot on through the main chamber intothe auxiliary chamber. This is advantageous since the physical conditionof the spray determines the type of chamber which is best suited to burnthe fuel. For a finely atomized body of fuel dispersed in air,quiescence is highly desirable, since the air and fuel particles are inideal condition for combustion. On the other hand, a body of fuelwhichis in a substantially liquid condition must be mixed with air before itwill burn, and requires turbulent air to break it up, mix with it, andproduce the proper conditions for eflicient combustion. Also it ishighly desirable that there be in each chamber sufilcient air forburning the fuel under the conditions existing in that chamber. If, forexample, 70% to 75% of the fuel is finely atomized in the main chamberand a core comprising 30% or 25% of the fuel passes on into theauxiliary chamber,

the amount of air in the respective chambers should be proportioned inapproximately the same ratio, although extra air for thorough combustionmay be provided where the conditions of combustion require it.

In the quiescent chamber! the highly atomized part of the fuel will burnsmoothly and quickly with a very slight ignition lag. Thefueisensitivity of the engine is determined largely by the dimensions ofthe main combustion chamber 1,

since this chamber must have an axial dimension large enough so that thefuel envelope mixes with the air and no appreciable impingement of theatomized fuel occurs on thewall opposite chamber should be adjustedsufficiently to the degree of compression, shape of nozzle tip andinjection pressure to prevent any substantial impingement upon the wallsof the main combus tion chamber in order to best effect the objects ofthis invention. This same consideration determines the startingqualities of the engine,.

the air and burns to start the engine. It has been found in practicethat in an engine in which the compression pressure is approximately 380pounds, and fuelis injected from a pintle type nozzle under a pressureof 1600 pounds per square inch that a distance of nearly 3 inches ismost advantageous to completely stop the spray envelope of the jet.

The dimension from the nozzle tip to the orifice of the auxiliarychamber also physically establishes a lag between the combustion of theatomized fuel in the quiescent chamber and the combustion of the liquidcore, since the latter must travel entirely across the main chamberbefore it can enter the turbulent chamber, and since it must circulatein the turbulent chamber for a period of time before it can becomesuiiiciently broken up to be in condition for combustion. The liquidcore can actually travel through a burning mass in the main chamber 1and remain in a substantially liquid condition having only asmailouterlayerburnedduringitspassage. The majorpartof thecorewillstillentertheauxiliarychamberasaooarsespray. Intheoperationofthe engine,ithasbeenfoundthattheflnely atomized fuel envelope burnsalmost as soon as it is injected into the chamber I, and an indicatorcard shows a consequent moderate rate of progressive pressure rise. Thecentral heavy core moves across the open combustion space and enters theauxiliary combustion chamber which is at such a distance from the pointof injection of the fuel that the core does not burn until later in thecycle after the introduction and bm'ning of the outer spray envelope inthe open chamber. The core is taken up in the rotary swirl of air in theauxiiiary'combustlon chamber and is vaporized and burned, setting up avery high pressure inside the auxiliary chamber. This pressure is chokedby the passage 2| so that it cannot act directly on the piston, butrather is throttled by the passage 2|, into the open chamber to act onthe piston head as it recedes on the pressure stroke of the engine. Thedimension of the main combustion chamber between the fuel injectionnozzle and the orifice of the passage 2| is so great that as the gasesissue from the chamber 8 they will not impinge on and burn the tip ofthe 4 nozzle.

cationthereof; it will be understood that variations may be made whileretaining essential features of this invention.

a As indicated, one of the important features is the provision of arelatively quiescent body of air into which the fuel jet is directed andinto which all of the fuel that can be suiiiciently atomized isdistributed, so that full advantage is taken of the atomization effectedby the injection,

while the relatively solid core of the fuel iet moves on into aturbulent mass of air that eifects its atomization It is preferable thatthese two bodiesof airshallbeinaboutthe sameproportion to each other asare the two portions of fuel that enter the respective bodies of air.

Other changes within the scope of the appended claims may be madewithout departing from the I invention.

Having thus described my invention, what I I claim as new, and desire tosecure by United States Letters Patent, is:

1. In an internal combustion engine having a 10 cylinder and a pistontherein, means providing a main .combustion chamber and an auxiliarycombustion chamber communicating with the main chamber, means to injecta jetof fuel across said main chamber toward said auxiliary lo chamber,said iet consisting of a spreading, highly atomized envelope and acoarsely atomized core, said main chamber containing relatively 1quiescent air and arranged to receive and permit the normal spreading ofsaid highly atomized 20 portion of the fuel within its quiescent air,and said auxiliary combustion chmnber arranged to receive said core, thecommunication between said main chamber and said auxiliary chamber beingsuchas to produce a swirl of air in said auxiliary chamber, thevolumetric ratio of the main combustion chamber to the auxiliarycombustion chamber being substantially equal to the ratio between theparts of the fuel received in the respective chambers.

2. In an internal combustion engine. a cylinder head adapted to overliea cylinder in which a piston operates and having main and auxiliarycombastion chambers, means to inject a jet of fuel across said mainchamber toward said auxiliary chamber, said iet consisting of aspreading, highly atomized portion and a coarsely atomized core, saidmain combustion chamber containing relatively quiescent air and arrangedto receive and permit the normal spreading of said highly atomizedportion of the fuel within its quiescent air and proportioned to containthat portion of the air charge used in burning said highly atomizedportion, and said auxiliary combustion chamber arranged to-receive saidcore and proportioned to contain that portion of the air charge used inburning said core, and means to produce a swirl of air in said auxiliarycombustion chamber.

ROBERT P. RAMSEY. 5o

